| Message ID | 1439563268-13418-3-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Hi Marc, On Fri, Aug 14, 2015 at 03:41:07PM +0100, Marc Zyngier wrote: > When find_and_init_phbs() looks for the probe-only property, it seems > to trust the firmware to be correctly written, and assumes that there > is a parameter to the property. > > It is conceivable that the firmware could not be that perfect, and it > could expose this property naked (at least one arm64 platform seems to > exhibit this exact behaviour). The setup code the ends up making > a decision based on whatever the property pointer points to, which > is likely to be junk. > > Instead, let's check for the validity of the property, and ignore > it if the firmware couldn't make up its mind. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > arch/powerpc/platforms/pseries/setup.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c > index df6a704..6bdc1f9 100644 > --- a/arch/powerpc/platforms/pseries/setup.c > +++ b/arch/powerpc/platforms/pseries/setup.c > @@ -490,14 +490,19 @@ static void __init find_and_init_phbs(void) > */ > if (of_chosen) { > const int *prop; > + int len; > > prop = of_get_property(of_chosen, > - "linux,pci-probe-only", NULL); > + "linux,pci-probe-only", &len); > if (prop) { > - if (*prop) > - pci_add_flags(PCI_PROBE_ONLY); > - else > - pci_clear_flags(PCI_PROBE_ONLY); > + if (len) { > + if (be32_to_cpup(prop)) > + pci_add_flags(PCI_PROBE_ONLY); > + else > + pci_clear_flags(PCI_PROBE_ONLY); > + } else { > + pr_warn("linux,pci-probe-only set without value, ignoring\n"); > + } This seems essentially identical to the pci-host-generic version. Is there a way we can factor it out so there's only one copy? > } > } > } > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Bjorn, On 14/08/15 15:57, Bjorn Helgaas wrote: > Hi Marc, > > On Fri, Aug 14, 2015 at 03:41:07PM +0100, Marc Zyngier wrote: >> When find_and_init_phbs() looks for the probe-only property, it seems >> to trust the firmware to be correctly written, and assumes that there >> is a parameter to the property. >> >> It is conceivable that the firmware could not be that perfect, and it >> could expose this property naked (at least one arm64 platform seems to >> exhibit this exact behaviour). The setup code the ends up making >> a decision based on whatever the property pointer points to, which >> is likely to be junk. >> >> Instead, let's check for the validity of the property, and ignore >> it if the firmware couldn't make up its mind. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> arch/powerpc/platforms/pseries/setup.c | 15 ++++++++++----- >> 1 file changed, 10 insertions(+), 5 deletions(-) >> >> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c >> index df6a704..6bdc1f9 100644 >> --- a/arch/powerpc/platforms/pseries/setup.c >> +++ b/arch/powerpc/platforms/pseries/setup.c >> @@ -490,14 +490,19 @@ static void __init find_and_init_phbs(void) >> */ >> if (of_chosen) { >> const int *prop; >> + int len; >> >> prop = of_get_property(of_chosen, >> - "linux,pci-probe-only", NULL); >> + "linux,pci-probe-only", &len); >> if (prop) { >> - if (*prop) >> - pci_add_flags(PCI_PROBE_ONLY); >> - else >> - pci_clear_flags(PCI_PROBE_ONLY); >> + if (len) { >> + if (be32_to_cpup(prop)) >> + pci_add_flags(PCI_PROBE_ONLY); >> + else >> + pci_clear_flags(PCI_PROBE_ONLY); >> + } else { >> + pr_warn("linux,pci-probe-only set without value, ignoring\n"); >> + } > > This seems essentially identical to the pci-host-generic version. > Is there a way we can factor it out so there's only one copy? Probably. drivers/of/of_pci.c seems like a good landing place for it. I'll hack something and repost it. Thanks, M.
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index df6a704..6bdc1f9 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -490,14 +490,19 @@ static void __init find_and_init_phbs(void) */ if (of_chosen) { const int *prop; + int len; prop = of_get_property(of_chosen, - "linux,pci-probe-only", NULL); + "linux,pci-probe-only", &len); if (prop) { - if (*prop) - pci_add_flags(PCI_PROBE_ONLY); - else - pci_clear_flags(PCI_PROBE_ONLY); + if (len) { + if (be32_to_cpup(prop)) + pci_add_flags(PCI_PROBE_ONLY); + else + pci_clear_flags(PCI_PROBE_ONLY); + } else { + pr_warn("linux,pci-probe-only set without value, ignoring\n"); + } } } }
When find_and_init_phbs() looks for the probe-only property, it seems to trust the firmware to be correctly written, and assumes that there is a parameter to the property. It is conceivable that the firmware could not be that perfect, and it could expose this property naked (at least one arm64 platform seems to exhibit this exact behaviour). The setup code the ends up making a decision based on whatever the property pointer points to, which is likely to be junk. Instead, let's check for the validity of the property, and ignore it if the firmware couldn't make up its mind. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/powerpc/platforms/pseries/setup.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)